The sum of first three common multiples of 3, 4 and 9 is (A) 108 (B)

1.	The sum of first three common multiples of 3, 4 and 9 is (A) 108 (B) 144 (C) 252 (D) 216
Answer» The correct option is (D) 216. First we have to find out common multiples of 3 , 4 and 9, For that find L.C.M of 3 ,4 and 9 3 \| 3 , 4 , 9 __________ 1 , 4 , 3 L. C.M ( 3 , 4 ,9 ) = 3 × 4 × 3 = 36 Now multiples of 36 = { 36 , 72 , 108, ....} Sum of first three common multiples of 3 , 4 , and 9 = 36 + 72 + 108 = 216

The sum of first three common multiples of 3, 4 and 9 is (A) 108 (B) 144 (C) 252 (D) 216

Answer»

The correct option is (D) 216.

First we have to find out common multiples of 3 , 4 and 9,

For that find L.C.M of 3 ,4 and 9

3 | 3 , 4 , 9

__________

1 , 4 , 3

L. C.M ( 3 , 4 ,9 ) = 3 × 4 × 3 = 36

Now multiples of 36 = { 36 , 72 , 108, ....}

Sum of first three common multiples of 3 , 4 , and 9 = 36 + 72 + 108 = 216